Unfortunately no luck:
# nsenter -t 10111 umount -l /var/snap/lxd/common/shmounts
umount: /var/snap/lxd/common/shmounts: not mounted.
# nsenter -t 10111 umount -l /var/snap/lxd/common/shmounts/storage-pools/lxd/containers/vtiger
umount: /var/snap/lxd/common/shmounts/storage-pools/lxd/containers/vtiger: no mount point specified.
Edit:
Wait. This worked:
nsenter -t 10111 -m umount -l /var/snap/lxd/common/shmounts/storage-pools/lxd/containers/vtiger
Now grep lxd/containers/vtiger /proc/*/mountinfo does returning nothing.
But when I now try to start the container again I get a new error:
# lxc start vtiger
Error: Common start logic: mkdir /var/snap/lxd/common/lxd/shmounts: file exists
Further investigation shows this:
# readlink /var/snap/lxd/common/lxd/shmounts
/var/snap/lxd/common/shmounts/instances
# stat /var/snap/lxd/common/shmounts/instances
stat: cannot stat '/var/snap/lxd/common/shmounts/instances': No such file or directory
Is this because I also tried to unmount /var/snap/lxd/common/shmounts?